Glass FRP-Reinforced Geopolymer Based Columns Comprising Hybrid Fibres: Testing and FEA Modelling

This study seeks to evaluate the effectiveness of glass-FRP-reinforced geopolymer concrete columns integrating hybrid fibres (GFGC columns) and steel bar-reinforced geopolymer concrete columns incorporating hybrid fibres (SFGC columns) under eccentric and concentric loadings. Steel fibre (SF) and polypropylene fibres (PF) are two types of fibres that are mixed into hybrid fibre-reinforced geopolymer concrete (HFRGC). Eighteen circular concrete columns with a cross-section of 300 mm × 1200 mm were cast and examined under axial loading up to failure. Nine columns were cast with glass-FRP rebars, whereas the other nine were cast with steel rebars. Using ABAQUS, a nonlinear finite element model was established for the GFGC and SFGC columns. The HFRGC material was modelled using a simplified concrete damage plasticity model, whereas the glass-FRP material was simulated as a linear elastic material. It was observed that GFGC columns had up to 20% lower axial strength (AST) and up to 24% higher ductility indices than SFGC columns. The failure modes of both GFGC and SFGC columns were analogous. Both GFGC and SFGC columns revealed the same effect of eccentricity in the form of a decline in AST. A novel statistical model was suggested for predicting the AST of GFGC columns. The outcomes of the experiments, finite element simulations, and theoretical results show that the models can accurately determine the AST of GFGC columns.

Mechanical Properties of High-Performance Hybrid Fibre-Reinforced Concrete at Elevated Temperatures

Deterioration of concrete’s integrity under elevated temperature requires an alteration in its composition to have better thermal stability. Fibre-reinforced concrete has shown significant improvements in concrete strength and this paper aimed to investigate the influence of steel (ST) and polypropylene (PP) fibres on the behaviour of high-performance concrete (HPC) exposed to elevated temperatures. Six mixtures were prepared and cast by adding one or two types of polypropylene fibre (54 and 9 mm) at 0.25 or 0.5% and either singly or in a hybrid combination, along with a fixed volumetric content at 1% of five-dimensional hooked steel (5DH) fibres. At the age of 28 days, samples were heated to the targeted temperature of 800 °C and cooled down naturally to the laboratory temperature. Visual inspection, flexural, split tensile and compressive strengths were examined before and after the exposure to elevated temperatures. Results exhibited that the hybridization of long and short PP fibres, along with the ST fibres, has notably improved all residual mechanical properties of HPC and kept the integrity of concrete after exposure to elevated temperatures. In addition, PP fibres can significantly prevent spalling, but ST fibres were ineffective in mitigating explosive spalling in beams specimens.

Preliminary Study of the Mechanical Properties of Hybrid Fibres Reinforced Unsaturated Polyester Composites

This research project investigates the mechanical properties of the corn husk fibre reinforced unsaturated polyester composite (CHFPC) and hybrid fibre (corn husk/flax) reinforced unsaturated polyester composite (HFPC) at different fibre orientations. The tensile and flexural properties of CHFPC and HFPC were manipulated by the different degrees of fibre orientations of 0°, 45°, and 90°. Both CHFPC and HFPC with 0° of fibre orientation had the highest tensile strength and flexural strength. Moreover, the tensile and flexural modulus of specimens with 0° orientation had the highest result compared to 45° and 90° orientations. However, for the elongation at break during tensile testing, 0° orientation had the highest strain, more than unsaturated polyester (UPR) and other composites. The tensile and flexural strengths of HFPC specimens with 0° fibre orientation were higher than that of CHFPC. Besides, the tensile modulus and flexural modulus of HFPC also increased as compared to CHFPC. The elongation at break of HFPC for tensile testing had the highest strain compared to CHFPC. The results showed that the mechanical properties of the hybrid fibre composite performed better compared to the single fibre composite. Moreover, the corn husk fibre (CHF) and flax fibre (FF) acted as reinforcements to enhance the mechanical properties of the UPR composites.

Shear Strength of Hybrid Fibre-Reinforced Ternary Blend Geopolymer Concrete Beams under Flexure

The need to promote sustainable civil infrastructure is one of the most important concerns in the construction industry. Geopolymer composites are one of the promising eco-friendly materials for the development of low carbon concrete. The main objective of this experimental investigation is to study the effect of hybrid fibres on the shear strength of flexural members made with ternary blend geopolymer concrete (TGPC). A total number of 27 reinforced concrete beams of size 100 × 150 × 1200 mm3 were cast and tested for shear. M55 grade of concrete was considered in this study. Crimped steel fibres and polypropylene fibres with an aspect ratio of 66 and 300, respectively, were used in this work. The main variables considered in this investigation involve two volume proportions of steel fibres, viz., 0.5% and 1% as well as four volume proportions of polypropylene fibres viz., 0.1%, 0.15%, 0.2% and 0.25%. The hybrid fibre-reinforced ternary blend geopolymer concrete (HTGPC) beams were compared with TGPC beams without fibres. From the test results, it was clear that incorporating hybrid fibres improved the shear strength and changed the type of failure of the beam from shear to flexure. Moreover, a method to predict the ultimate shear strength of HTGPC was proposed, and the estimated values were found to be the same as the test results.

Application Of Hybrid Fibre Concrete As Advanced Material For Concrete Water Tank Construction

The challenge of construction and the complexity of civil engineering systems, especially in the construction of water tanks, are catching people’s attention around the world. Concrete, which is a priority feature and a mandatory used material, must have a very high strength and an acceptable degree of workability and properties. Efforts are being made in the field of concrete production to create and expand these mixtures of unusual characteristics and behaviors. The used of the hybrid fibre concrete in the concrete wall can reduce the costing factor in terms of constructions and maintenances beside that the quality assurance is highlighted. In addition, the sustainability in the water tank construction in Malaysia can be achieved using the advanced material in the construction.